Neutron Beam Therapy (NBT) - CAM 757HB

Neutron beam therapy (NBT) is a type of radiation treatment that uses a particle accelerator, so is not readily available in most of the country. Protons from the accelerator create a neutron beam that attacks cancer cells with more power than conventional radiation therapy. Neutrons are much heavier than photons, and thus appear to be more effective in destroying very dense tumors. With neutron beam treatment, the risk of side effects on healthy tissue near the cancer site is greater, requiring equipment to precisely focus the beam and block exposure to any surrounding tissue. Currently, both the availability and the criteria for use are very limited. 

NBT has been employed mainly for the treatment of the salivary gland cancers. It has also been used to treat other malignancies such as soft tissue sarcoma, lung, pancreatic, colon, kidney and prostate cancers. Nevertheless, NBT has not gained wide acceptance because of the clinical difficulty in generating neutron particles and limited publications.  

The safety and efficacy of neutron beam radiation therapy has not been established in the published medical literature. Complication rates were increased for NBT compared to other forms of external beam radiation therapy, and questions remain with regard to patient selection criteria, technical parameters and comparative efficacy to other treatment modalities.

Indications for Neutron Beam Therapy:

  • Neutron beam treatment is indicated for salivary gland cancers that are inoperable, recurrent, or are resected with gross residual disease or positive margins (ACS, 2017).
  • Other uses of neutron beam therapy are considered investigational/unproven and therefore are NOT MEDICALLY NECECESSARY because their effectiveness for these indications has not been established.


  1. Airoldi M, Cortesina G, Giordano C, et al. Update and perspectives on non-surgical treatment of salivary gland malignancies. Acta Otorhinolaryngol Ital. 2003; 23(5):368-376.
  2. American Cancer Society (ACS). Radiation Therapy for Salivary Gland Cancer. September 28, 2017. Accessed May 1, 2018.
  3. American Society of Clinical Oncology (ASCO). Salivary Gland Cancer Treatment. .  Updated April 2, 2013.  Accessed November 6, 2013.
  4. Chou RH, Wilder RB, Wong MS, et al. Recent advances in radiotherapy for head and neck cancers. Ear Nose Throat J. 2001; 80(10):704-707, 711-714, 716 passim.
  5. Davis C, Sikes J, Namaranian P, et al. Neutron beam radiation therapy: An overview of treatment and oral complications when treating salivary gland malignancies. J Oral Maxillofac Surg. April 2016; 74(4):830-835. Accessed May 17, 2016.
  6. Day TA, Deveikis J, Gillespie MB, et al. Salivary gland neoplasms. Curr Treat Options Oncol. 2004; 5(1):11-26.
  7. Eng TY, Thomas CR, Herman TS. Primary radiation therapy for localized prostate cancer. Urol Oncol. 2002; 7(6):239-257.
  8. Engenhart-Cabillic R, Debus J, Prott FJ, et al. Use of neutron therapy in the management of locally advanced nonresectable primary or recurrent rectal cancer. Recent Results Cancer Res. 1998; 150:113-124.
  9. Huber PE, Debus J, Latz D, et al. Radiotherapy for advanced adenoid cystic carcinoma: Neutrons, photons or mixed beam? Radiother Oncol. 2001; 59(2):161-167.
  10. Kankaanranta L, Seppälä T, Koivunoro H, et al. l-boronophenylalanine-mediated boron neutron capture therapy for malignant glioma progressing after external beam radiation therapy: A phase I study. Int J Radiat Oncol Biol Phys. 2011; 80(2):369-376.
  11. Lindsley KL, Cho P, Stelzer KJ, et al. Fast neutrons in prostatic adenocarcinomas: Worldwide clinical experience. Recent Results Cancer Res. 1998; 150:125-136.
  12. Murray PM. Soft tissue sarcoma of the upper extremity. Hand Clin. 2004; 20(3):325-333, vii.
  13. National Comprehensive Cancer Network (NCCN).  Head and Neck Cancers. 1.2016. Accessed May 17, 2016.
  14. Purins A, Mundy L, Hiller J. Boron neutron capture therapy for cancer treatment. Horizon Scanning Prioritising Summary. Adelaide, SA: Adelaide Health Technology Assessment (AHTA); October 2007.
  15. Strander H, Turesson I, Cavallin-Stahl E. A systematic overview of radiation therapy effects in soft tissue sarcomas. Acta Oncol. 2003; 42(5-6):516-531.

Coding Section

Code Number Description
CPT 77422 High energy neutron radiation treatment delivery; single treatment area using a single port or parallel-opposed ports with no blocks or simple blocking (Report required)
  77423 1 or more isocenter(s) with coplanar or non-coplanar geometry with blocking and/or wedge, and/or compensator(s) (Report required)

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross Blue Shield Association technology assessment program (TEC) and other nonaffiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

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